Cartridge power feed mechanism



July 3, 1945. R. N. NELSON CARTRIDGE POWER FEED MECHANISM Filed April 27, 1942 2 Sheets-Sheet l 3mm/Mw Eid-mrd N- NELSm-L @3M VQ# @M July 3, 1945 R. N. NELsoN CARTRIDGE POWER FEED MECHANISM Filed April 27, 1942 2 Sheets-SheetZ NELsm-L Patented July 3, 1945 UNITED STATES PATENT ori-ICE (Granted under the act'oi' March 3, 1883, as amended April 30, 1928: 370 0. G. 757) 1 Claim.

, 'The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me oi' any royalty thereon.

This invention relates to an automatic weapon with a self-contained auxiliary power feed mechanism.l Y

Exceptionally high speed guns are necessary in modern warfare. These guns require an abundant supply of ammunition which is made available for instant use by threading long disintegrating belts to conventional feed mechanisms. This is particularly true concerning aircraft and other military vehicles which are employed for long range operations where the belts often reach a length of about one hundred feet. The conventional timed feed mechanism of a gun of the Browning type is unable to accommodate such a heavy load and also perform its normal high speed functioning without seriously impairing 'the operation of the weapon.

It is therefore a primary object of this invention to provide a gun with a self-contained power booster feed for performing the heavy belt lifting operation in such a manner that the conventional timed feed mechanism performs its normal functions under ideal conditions. An object of the invention is to provide a power feed which is directly coupled to thefrecoiling barrel or power source of an automatic weapon.

Another object of this invention is to provide an auxiliary feed mechanism which can be mounted on the standard machine gun with but a few simple alterations in the present gun structure.

A further object of the invention is to provide an auxiliary power feed which is adapted for mounting on a gun employing either a right or left hand feed.

Y. A still further object of the invention is to provide a feed mechanism which is simple in construction, strong, durable, and adapted for quick convenient mounting with a few simple tools on an automatic gun of the Browning type.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawins in which:

Fig. 1 is a side elevational view of the power feed with a portion of the cartridge guide broken away and mounted on the left side of a Browning typ' Sun (shown in phantom) adjacent the standard belt feed mechanism;

Fig. 2 is a vertical sectional view of the gun rection of the muzzle end of the gun;

Fig. 3 is a plan view of the auxiliary feed mechanism with the adjoining gun portion shown in phantom in horizontal section along the axis of the barrel;

Fig. 4 is a vertical sectional view on thel line l-d of Fig. 1;

Figs. 5 and 6 are vertical longitudinal sectional il/iiews2 on the lines 5-'5 and 6 6 respectively of Fig. 7 is a view in side elevation of the body plate showing the guideway for the feed slide;

Fig. 8 is a plan view thereof;

Fig. 9 is a sectional view on the line Q of Fig. 7;

Fig. 10 is a side elevational view of the cartridge guide;

Fig. 11 is a view in side elevation of the power feed slide;

Fig. l2 is a sectional view on the line iZ-i of Fig. 11, and

Fig. 13 is a perspective view of the rocker assembly for actuating the power feed slide.

Referring to the drawings, there is shown in Figs. 1, 3 and 4 a portion of a machine gun which includes a barrel I0 slidably mounted in a. trunnion block II. A pair of side plates I2 are secured to the trunnion block by suit/able means such as rivets I3. Positioned near the top of the gun'are the conventional cartridge feed passage Il, the belt feed slide I5 and associated belt feed pawl I6, and the belt holding pawl I'I. Rigidly secured to the left side plate and the trun` nion block of the gun by a pair of bolts I8 is a body plate I9 which has centrally located therein a recessed guideway 20. A power feed slide 2I`is arranged to reciprocate therein and has pivotally mounted tlereon a feed pawl 22 whose upper end is urged outwardly by resilient means such as a spring 23. A rectangular cartridge guide 24 is mounted on the body plate I9 by a pair of screws 25. Pivotally mounted on the external side of the guide is a holding pawl 28 which is'urged inwardly through theupper of a pair of apertures 2l in the guide by a coil spring 28, see Fig. 4. This pawl assembly may be inverted in its holder or mounting so that the pawl projects through the lower aperture for a purpose which will be explained later.

Secured to the inner side of a projecting leg 29 of the trunnion block by a bolt 30 is a bracket 3i which carries a cylindrical bearing 32. This bearing is adapted to receive one end of an actuator shaft 33 while the other end is journaled in an oppositely disposed bearing 34 in the lower end of the body plate I9. A second bearing is present on the other lower corner of the body plate (Fig. 1) for a purpose which will be explained later.

Referring to Figs. 4 and 5, shaft 33 has mounted thereon an actuator 35 which has a. partially circular aperture 36 which conforms to the cross section of the shaft 33. This arrangement in commotion with a looking pin 31 secures the actuator in proper spaced relation on the shaft. Actuator 35 is an upwardly extending nger with a curved free end 38 which is adapted to engage the lower rear face 39 of the front portion of the barrel extension 40. The barrel I is received in threaded engagement with this portion of the barrel extension 40. Coupled to the shaft 33 but angularly displaced from the actuator 35. as shown in Fig. 5. is an actuator return arm 4i. This arm at its upper end is provided with a comb portion 42 which rides in one of the notches 43 in the sides of the trunnion block II. A nose 44 on the comb engages the front face 45 of the barrel extension so that when the barrel reciprocates the shaft 33 is oscillated through the intermediation of the actuator 35 and the actuator return arm 4I. The comb 42 on the arm 4I is designed to retain a portion of the arm in the notch 43 of the trunnion block during the entire period of oscillation of the arm thereby aiding in retaining the oscillating parts in their proper positions.

Coupled to one end of the shaft 33 so as to oscillate therewith is the actuating lever 46 for the power feed slide 2l, see Figs. 1. 4, 5 and 13. Lever 46 is arranged to move in a space or channel 41 intermediate the front and back faces of the body plate I9, as shown in Fig. 6. The organization comprising the actuator, the actuator return arm, the oscillating shaft, and the actuating lever coact to convert the longitudinally reciprocating motion imparted by the barrel into vertical reciprocating movement of the power feed slide.

Details of construction of the body plate I9 are shown in Figs. 7-9. Guideway 20 is undercut on the side portions 48 so as to provide a pair of vertical shoulders 49. These shoulders serve t0 confine the power feed slide 2| in the channel during its reciprocating movement. The body plate is symmetrical on both sides of the guideway. A pair of bearings 34 are provided at the lower corners and the channel 41 has the same conguration on both sides of the guideway. Since both sides of the gun are provide with symmetrically located tapped holes to accommodate the bolt fasteners I8, the body plate I9 may be secured to either side. With a pair of bearings 34 in the lower corners of the plate, a bearing is always available to retain the shaft 33 in its proper position regardless of which side of the gun the feed mechanism is to be mounted on. Countersunk holes 59 are provided for the screws 25 which secure the guide 24 to the plate I9. This enables the plate to rest fiat against a side plate of the gun.

The cartridge guide 24 rather generally conforms to the shape of a cartridge as shown in.

Fig. 3. A vertical internal rib I acts as a steadying member for the neck end of a cartridge as it passes through the guide. Flared mouths 52 are provided which aid in conducting the belt into the guide and in the formation of a bight in the cartridge belt as will be explained in another part of the specification.

Slide 2| is a substantially U-shaped member adapted to reciprocate in the guide channel 29. Parallel side walls 53 house a pawl shaft 54 and the power feed pawl 22. A spring seat 55 assists in retaining the spring 23 in its proper position. The rear 'of the slide is provided with a groove 53 which is conditioned to receive in sliding engagement a pin 51 on one end of the actuating lever 45, see Figs. 1. 6, 11 and l2. As the lever 45 oscillates, pin 51 slides in the groove 55 while the power feed slide 2l is being reciprocated. An additional channel 53 receives the arcuate end 59 of the lever 46. The lower end of the power feed pawl 22 is arranged to engage the curved seat 60 on the slide so as to limit the outward movement of the pawl, see Fig. 4.

The Browning gun can be quickly conditioned to receive the power feed mechanism in the following manner. A rivet ls removed from the side plates on each side of the gun under the standard feed mechanism and the holes are tapped to accommodate bolt I8. An additional hole is drilled and tapped in the side plates and trunnion block on each side of the gun to receive the second bolt I8. The inner heads of two pair of rivets are ground flush with the legs of the trunnion block to permit the movement of the actuating lever 46. Then a pair of spaced notches 43 are cut in the trunnion block adjacent the front face 45 of the barrel extension 4I) as shown in Figs. 2 and 4 and the gun is modified to carry the power feed mechanism.

This mechanism may be attached to the gun in the following manner. The guide 24 is secured to the body plate I9 by screws 25. The pawl 25 is arranged so that it is urged through the upper aperture 28. Body plate I 9 is fastened to the gun by the pair of bolts I8. Power feed slide 2l is then inserted in the guideway in the block, pawl 22 having been previously pivotally mounted in the slide. The shaft 33 including the actuator, the actuator return arm and the slide actuating lever arrangement are now mounted in-their operative position. This is accomplished by placing pin 51 of the slide actuating lever 46 in its groove 56 in the slide 2I and by inserting the proper end of the shaft 33 in its bearing 34 in the body plate I9. The opposite end of the shaft is inserted in the bearing 32 in bracket 3l whereupon the bracket is secured to the leg 29 by bolt 30. This operatively couples the power feed mechanism to the gun.

When it is desired to provide the gun with a right hand power feed, the body plate I9 is removed from the left side of the gun, the screws backed off, the guide 24 inverted, and the pawl assembly reversed so that the pawl 25 projects through the other of the two apertures 21. Then the screws are tightened to the body plate. The actuator return arm 4I is placed on the other side of the actuator 33 on shaft 33. Then slide actuating lever is removed from the shaft 33, inverted and placed on the other end of the Shaft. Body plate I9 is rotated through azimuth and secured to the opposite side of the gun by bolts I9 which are tightened in the holes already provided. The shaft assembly is inserted in its proper position in bearing 34 in the plate I9 and in power feed slide 2l and then the bracket 3| is fastened to the opposite side of the gun so as to journal the other end of the shaft 33. The auxiliary feed mechanism is now conditioned for a right hand feed. This transposition can be effected by the use of a few simple tools. The standard feed mechanism on the gun is, of course, reversed to conform to the direction of feed of the auxiliary feed device in the usual manner.

The operation of the power feed mechanism in conjunction with the gun is as follows: When the gun is fired the barrel l recoils. Since the body plate i9 is coupled to the stationary trunnion block of the gun, no movement of that member occurs. During the period of recoil of the barrel, the rear face 39 of the barrel extension 40 thrusts the actuator 35 backward thereby rocking shaft 33 and lifting the actuating lever 46. Actuator return arm 4l is also rocked and moves in the guide notch 63' in the trunnion block. The upward movement of actuating lever 46 lifts the power feed slide vertically in its guide channel 20 in the fixed body plate i9. Because of the arcuate path taken by the actuating lever 46, the pin 51 on the lever slides horizontally in the groove 56 in the rear face of the power feed slide.

The disintegrating belt has been threaded through the power feed mechanism and interconnected with the conventional feed slide I5, feed pawl i6 and the holding pawl I1 of the gun as shown in Figs. 2 and 4. Upon recoil of the gun the standard feed slide l5 moves to the right as viewed in Fig. 4 by conventional gun mechanism so that the pawl i6 engages behind the next cartridge in the belt. Pawl I1 prevents any backward movement of the upper section of the belt in a manner well understood in the art.

Since the recoil of the barrel members acts upon the lever system of the power feed mechanism to lift the slide 2|, the power feed pawl 22 coupled theretoengages behind ,an adjacent cartridge in the guide 24 and lifts the entire depending belt upward. The stroke of the slide 2| is suflicient to produce a loop or bight in the belt above the exit of the guide 24 and is represented by the cartridge 6I shown in phantom. This stroke is also ample to permit the holding pawl 26 on the guide to engage behind the next preceding cartridge 62 to retain a loose, untensioned cartridge loop between the outlet from the guide and the entrance to the standard partridge feed passage of the automatic gun. The stop pawl 26 prevents any retrograde movement of the belt after a power feed stroke. The flared upper mouth 52 of the guide conveniently allows the belt to assume a loop.

While a comparatively small vloop is shown in Fig. 4, the belt may be threaded to the standard fed mechanism so that a larger loop of cartridges is available. The operation of the gun is unaffected when a somewhat larger loop is employed.

On counterrecoil of the barrel, the front face 4l of the barrel extension 40 thrusts the nose Il forward and rocks the actuator return arm Il downward in slot 43 in the trunnion block. This depresses the pawl actuating lever 46 and lowers the power feed slide in its guideway.

When the barrel is back in battery the pawl 22 on the power feed slide is again in position to pick up another cartridge and lift the belt upward toward the standard feed mechanism when ,the gun is fired.

During the counterrecoil stroke of the barrel, the conventional feed slide and pawl at the top o! the gun advance a small section of the belt a step equal to the pitch distance between cartridges whereby a cartridge is presented to the chamber of the barrel.

It is to be noted that the belt load on the conventional feed mechanism of the gun during its feeding stroke is negligible since it comprises but a few cartridges. As shown in Fig. 4 the load is only four cartridges. The presence of the bight above the stop pawl 26 on the cartridge guide eliminates any tension in the belt in the immediate vicinity of the cartridge feed passage of the gun proper. This permits the conventional timed feed mechanism of the gun to function at all times at a high and uniform rate of speed. The length and weight of the entire belt is no longer a factor affecting the speed of operation.

Since the recoiling barrel of the gun is a direct power source, tremendous force is available for use in lifting the heavy bel-t load. The conventional feed mechanism is actuated by the bolt, a driven member, having a limited amountl of energy available for feeding purposes. Energy in the recoiling barrel which would ordinarily be dissipated is utilized to materially reduce the burden on the standard feed mechanism. The operation of the power booster feed is coordir nated with that of the gun feed mechanism so that the greatest eiiiciency and best functioning of the gun is attained.

I claim:

An auxiliary feed mechanism adapted for use with a machine gun having a barrel and barrel extension reciprocable in recoil and counterrecoil and a frame comprising side plates having fastening means thereon and a cartridge belt feeding mechanism, said auxiliary feed mechanism comprising a body plate adapted for mounting on one of the side plates of the gun, said body plate having a. guideway for the reception of a feed slide, and fastening means for aligned engagement with the first mentioned fastening means whereby the said body plate is rotatable through azimuth about the axis of the guideway for attachment at will to either side plate of the gun, a feed slide reciprocable in said guideway, a feed pawl reciprocable in the guide- Way for feeding cartridges, a pair of bearings at opposite lower corners of the body plate, a bracket for attachment to one of said side plates directly opposite one of the bearings, a bearing in the bracket, means for securing the bracket to the side plate of the gun, a shaft rockably mounted in the bearing in the bracket and in a .preselected one of said pair of bearings in the body plate, an operating arm on the shaft and constructed for coupling at one of its ends to either end of the shaft and at its other end to the feed slide, an actuating lever having one end connected to the shaft and the other engageable behind a rear face on the barrel extension, a return lever detachably mounted on the shaft and positively coupled thereto, said lever having an end adapted to abut a front face of the barrel extension and adapted upon the counterrecoil of the gun to operate said lever to reciprocate the feed slide, a cartridge belt guide detachably secured to the body plate and having a belt passage therethrough, said guide having a pair of \vertically spaced apertures symmetrically disposed with respect to the top and bottom edges of the guide, and a rockable holding pawl pivoted to the guide and projecting in operative relationship through one of the' apertures of said cartridge belt guide.

RICHARD N. NELSON. 

